Process for production of fiber reinforced tape

ABSTRACT

The invention relates to a process for the production of a tape comprising a plurality of sheathed continuous multifilament strands, wherein each of the sheathed continuous multifilament strands comprises a core that extends in the longitudinal direction and a polymer sheath which intimately surrounds said core, wherein each of the cores comprises an impregnated continuous multifilament strand comprising at least one continuous glass multifilament strand, wherein the at least one continuous glass multifilament strand is impregnated with an impregnating agent, wherein the process comprises the steps of: d) providing the plurality of sheathed continuous multifilament strands, e) placing the plurality of sheathed continuous multifilament strands in parallel alignment in the longitudinal direction, f) grouping the plurality of sheathed continuous multifilament strands, wherein steps e) and f) are performed such that the sheathed continuous multifilament strand can be consolidated and g) subsequently consolidating the plurality of sheathed continuous multifilament strands to form the tape, wherein the sheathed continuous multifilament strands are prepared by the sequential steps of a) unwinding from a package the continuous glass multifilament strands, b) applying the impregnating agent to the continuous glass multifilament strands to form the impregnated continuous multifilament strands and c) applying the sheath of the thermoplastic polymer composition around the impregnated continuous multifilament strands to form the sheathed continuous multifilament strands, wherein the sheathed continuous multifilament strands of step d) are the sheathed continuous multifilament strands obtained by step c) and wherein the sheathed continuous multifilament strands of step d) are subjected to step e) without cutting.

The present invention relates to a process for the production of a fiberreinforced tape. The invention further relates to such tape, to alaminate or a woven fabric prepared from said tape, to an articlecomprising said tape or said laminate or woven fabric and to the use ofsaid tape and laminate and woven fabric in applications, such asautomotive applications.

Introduced more than a half century ago, fibre-reinforced plastics arecomposite materials with a wide range of applications in industry, forexample in the automotive industry. The term “composite” can apply toany combination of individual materials, for example to a thermoplasticpolymer (the matrix) in which fibres (reinforcing filler) have beendispersed. The reinforced plastics industry has used glass fibres indifferent forms for reinforcing polymer matrices to produce a diversityof products.

In the production of short glass fibre compositions or compounds,chopped strands of pre-determined length are mixed with a thermoplasticpolymer in an extruder, during which the integrity of the glass fibrestrands is destroyed and the glass fibres are dispersed throughout themolten thermoplastic polymer; due to fibre breakage the fibre length isdecreased during this process, typically to well below 1 mm. Long glassfibre-reinforced polymer compositions contain glass fibres having alength of at least 1 mm, often at least 2 mm and typically between 5 and20 mm. As a result, glass fibres in moulded articles made from longglass fibre-reinforced polymer compositions generally are of higherlength than in articles made from short glass fibre compositions,resulting in better mechanical properties. For that reason long glassfibre-reinforced polymer compositions are preferred for applicationswherein good mechanical properties are necessary.

However, reinforcement of a thermoplastic polymer by using glass adds alot of weight to an article, since the thermoplastic polymer generallyhas a lower density than glass. In order to be able to prepare lightweight articles, which still have sufficient strength, in recent years,long glass fibre-reinforced tapes have been introduced into the marketto allow for the production of light-weight articles with sufficientstrength due to the use of the reinforcing tape.

A special class of tapes are unidirectional tapes, which are tapes thathave fibers that extend substantially in the longitudinal direction.Such unidirectional tapes are typically used to prepare articles havingproperties that vary in one or more directions or dimensions.

Examples of unidirectional glass fiber tapes are known fromWO2016/142784A1. WO2016/142784A1 discloses a fiber-reinforced compositecomprising:

a matrix material including a thermoplastic material; and

a non-woven fibrous region comprising a plurality of continuous fibersdispersed in the matrix material;

wherein the width and the length of the non-woven fibrous region aresubstantially equal to the width and the length, respectively, of thefiber-reinforced composite;

wherein the non-woven fibrous region has a mean relative fiber areacoverage (RFAC) (%) of from 65 to 90 and a coefficient of variance (COV)(%) of from 3 to 20; and wherein each of the plurality of continuousfibers is substantially aligned with the length of the fiber-reinforcedcomposite.

Unidirectional composite fiber prepregs are for example described inWO2011/163365 A2 and composite fiber profiles are for example describedin WO2011/156693 A2.

Reinforced composites from thermoplastic materials combine the stiffnessprovided by the reinforcement with the advantageous properties of athermoplastic material, such as easy molding and plying of the materialabove a certain temperature and solidification below that temperature.

There is a need in the art for providing a unidirectional glass fibertape in an efficient manner.

It is an object of the invention to provide a unidirectional glass fibertapein an efficient manner.

This object is achieved by a process for the production of a tapecomprising a plurality of sheathed continuous multifilament strands,

wherein each of the sheathed continuous multifilament strands comprisesa core that extends in the longitudinal direction and a polymer sheathwhich intimately surrounds said core,

wherein each of the cores comprises an impregnated continuousmultifilament strand comprising at least one continuous glassmultifilament strand, wherein the at least one continuous glassmultifilament strand is impregnated with an impregnating agent,

wherein the process comprises the steps of:

d) providing the plurality of sheathed continuous multifilament strands,

e) placing the plurality of sheathed continuous multifilament strands inparallel alignment in the longitudinal direction,

f) grouping the plurality of sheathed continuous multifilament strands,wherein steps e) and f) are performed such that the sheathed continuousmultifilament strand can be consolidated and

g) subsequently consolidating the plurality of sheathed continuousmultifilament strands to form the tape,

wherein the sheathed continuous multifilament strands are prepared bythe sequential steps of

a) unwinding from a package the continuous glass multifilament strands,

b) applying the impregnating agent to the continuous glass multifilamentstrands to form the impregnated continuous multifilament strands and

c) applying the sheath of the thermoplastic polymer composition aroundthe impregnated continuous multifilament strands to form the sheathedcontinuous multifilament strands,

wherein the sheathed continuous multifilament strands of step d) are thesheathed continuous multifilament strands obtained by step c) andwherein the sheathed continuous multifilament strands of step d) aresubjected to step e) without cutting.

In the process according to the invention, the sheathed continuousmultifilament strands formed by step c) (the sheathed continuousmultifilament strands of step d)) are directly subjected to step e)without cutting. Thus, in these embodiments, the steps for making thesheathed continuous multifilament strands a)-c) and steps e)-g) areperformed in one manufacturing system. The process can be performed as acontinuous process, i.e. the continuous glass multiflament strands arecontinuously unwound for use in the process as the tape is formedcontinuously by the process.

Such continuous process is much more efficient and faster than a processin which the sheathed continuous multifilament strands formed by step c)are cut and made into bobins and the bobbins are unwound to be placed inparallel alignment in the longitudinal direction in step e). Thecontinuous process is easier to operate since it does not require manyseparate procedures. This results in a lower manufacturing cost.Moreover, the variations in the properties of tapes produced by thecontinuous process, such as tensile, flexural and impact properties, aresmall.

Preferably, the process of the invention involves no cutting until thetape of step g) is formed. Accordingly, preferably, the continuous glassmultifilament strands unwound in step a), the impregnated continuousmultifilament strands formed in step b), the sheathed continuousmultifilament strands formed in step c) are not cut during steps a)-g).

Steps a)-c) are described in detail in WO2009/080281A1, which documentis hereby incorporated by reference.

For purpose of the invention with ‘such that the plurality of sheathedcontinuous multifilament strand can be consolidated’ is meant that theplurality of sheathed continuous multifilament strands are placed insuch a vicinity to one another that they can be melted together.

Steps e) and f) can be performed by first placing the plurality ofsheathed continuous multifilament strands in parallel alignment in thelongitudinal direction after which the plurality of sheathed continuousmultifilament strands are grouped. However, steps e) and f) can also beperformed by first grouping the plurality of sheathed continuousmultifilament strands after which the plurality of sheathed continuousmultifilament strands is placed in a parallel alignment in thelongitudinal direction.

Steps e) and f) can also be performed in one and the same step, forexample by pulling the plurality of sheathed continuous multifilamentstrand through a slit die (a die with an opening in the form of arectangle, preferably a slit die having an opening with dimensions thatare comparable to the thickness and width dimensions of the tape to beproduced).

Step g) of the consolidation of the plurality of sheathed continuousmultifilament strand for form the tape is performed in a consolidationunit. An example of a consolidation unit includes but is not limited toa belt press.

Step g) is preferably performed by sequential steps of g1) heating andexerting pressure on the plurality of sheathed continuous multifilamentstrand to obtain a product made of consolidated strands and g2) coolingand solidifying the product obtained by step g1), e.g. by chill rolls, awater bath, a blower a fan or a high speed air knife.

Step g1) is preferably performed e.g. by sequential steps of g1a)melting the plurality of sheathed continuous multifilament strand tomerge the strands, e.g. by hot rolls, flat belts, an oven or a beltpress and g1b) exerting pressure on the product obtained by step g1a) toadjust its thickness, e.g. by calendaring rolls.

Step g1a) heats the plurality of sheathed continuous multifilamentstrand to melt them, so that they will be merged. This also improves theimpregnation of the impregnated continuous multiflamet strands in thethermoplastic polymer, which results in improved tape properties.Examples of units for performing step g1a) include hot rolls, flatbelts, an oven and a belt press. The use of hot rolls for step g1a) hasan advantage that it can be performed at a high speed. The advantage ofusing flat belts or belt press is that the tape directly contact withthe belt to achieve a good heat transfer, which results in a betterimpregnation. Step g1b) is performed at a lower temperature than theprevious step, which further improves the impregnation of theimpregnated continuous multiflamet strands in the thermoplastic polymer.This further achieves a good surface quality. Step g2) results in thefinal solid tape. This can be performed using chill rolls, whichadvantageously achieves a relatively slow cooling to reduce shrinkage.Some other possible cooling methods are water bath, blower, fan, highspeed air knife, etc. These technologies can reach fast cooling,especially water bath.

The process may further comprise the step h) of cutting the tapeobtained by step g) into desired length, which may be stacked or wound.

In another aspect, the invention relates to a tape obtained orobtainable by the process of the invention.

In another aspect, the invention relates to a laminate of a plurality oftapes of the invention. Within the framework of the invention, with‘laminate’ is meant an arrangement in which at least two plies (layers)of the tapes of the invention are present. For example, such laminatecontains 2, 3, 4, 5, 6, 7, 8, 9, 10, or more plies, wherein one plyconsists of the tape of the invention. For example, in the laminate, theplies may be positioned such that their respective sheathed continuousmultifilament strands are not parallel to each other. In case theirrespective sheathed continuous multifilament strands are positioned inrelation to one other in a substantially 90° angle, such laminate isusually referred to as cross-ply. Laminates of the invention can forexample be assembled or processed into two-dimensional orthree-dimensional structures, such as, for example, via winding and/orlay-up techniques.

In another aspect, the invention relates to a woven fabric made of aplurality of tapes of the invention. Any known methods for weaving tapesinto a woven fabric may be used.

In another aspect, the invention relates to an article comprising thetape of the invention, the consolidated laminate of the invention or thewoven fabric of the invention.

The tapes, laminates, woven fabrics or articles of the invention can forexample be used in an automotive application.

It has been found that the impact energy per unit of thickness is higherfor the tapes according to the invention which contain wax (impregnatingagent) as compared to the tapes which do not have wax in theircomposition. In addition, the E-modulus (also known as Young's modulusor stiffness) may be increased by the tapes of the invention as well.

Therefore, for tapes according to the invention, the impact energy perunit of thickness as measured according to the method as describedherein is higher as compared to tapes from a plurality of sheathedcontinuous multifilament strands having a core that is not impregnatedwith an impregnating agent.

In the context of the invention with ‘tape’ is meant an object whosethickness is very thin in relation to its length and width. That is, thetape has a high width to thickness ratio. Typically the width of a tapeis between 1-1500 times, for example 2-100 times, larger than thethickness. The length of the tape can be indefinite. The tape may have arectangular cross-, but may also have profiled sections (corrugated,ribbed etc.).

The tape of the invention may for example have a thickness in the rangefrom 0.1 to 10 mm and/or a width in the range from 1 to 4000 mm, forexample 10 to 400 mm.

Each core of a sheathed continuous multifilament strands comprises animpregnated continuous multifilament strands, for example one or moreimpregnated continuous multifilament strands. Preferably, the one ormore impregnated continuous multifilament strands form at least 90 wt %,more preferably at least 93 wt %, even more preferably at least 95 wt %,even more preferably at least 97 wt %, even more preferably at least 98wt %, for example at least 99 wt % of the core. In a preferredembodiment, each core consists of the one or more impregnated continuousmultifilament strands.

In the context of the invention with ‘extends in the longitudinaldirection’ is meant ‘oriented in the direction of the long axis of thesheathed continuous multifilament strand

The impregnated continuous multifilament strand is prepared from acontinuous glass multifilament strand and an impregnating agent.

The term intimately surrounding as used herein is to be understood asmeaning that the polymer sheath substantially entirely contacts thecore. Said in another way the sheath is applied in such a manner ontothe core that there is no deliberate gap between an inner surface of thesheath and the core containing the impregnated continuous multifilamentstrands. A skilled person will nevertheless understand that a certainsmall gap between the polymer sheath and the glass filaments may beformed as a result of process variations. Preferably, therefore, thepolymer sheath comprises less than 5 wt. % of said filament, preferablyless than 2 wt. % of filament based on the total weight of the polymersheath.

Preferably, the thickness of the polymer sheath in the sheathedcontinuous multifilament strand is between 200 and 1500 micrometer, forexample 500 and 1500 micrometer.

Glass fibres are generally supplied as a plurality of continuous, verylong filaments, and can be in the form of strands, rovings or yarns. Afilament is an individual fibre of reinforcing material. A strand is aplurality of bundled filaments. Yarns are collections of strands, forexample strands twisted together. A roving refers to a collection ofstrands wound into a package.

For purpose of the invention, a glass multifilament strand is defined asa plurality of bundled glass filaments.

Glass multifilament strands and their preparation are known in the art.

The filament density of the continuous glass multifilament strand mayvary within wide limits. For example, the continuous glass multifilamentstrand may have at least 500, for example at least 1000 glassfilaments/strand and/or at most 10000, for example at most 5000 gramsper 1000 meter. Preferably, the amount of glass filaments/strands is inthe range from 500 to 10000 grams per 1000 meterglass filaments/strand.

The thickness of the glass filaments is preferably in the range from 5to 50 μm, more preferably from 10 to 30 μm, even more preferably from 15to 25 μm. Usually the glass filaments are circular in cross sectionmeaning the thickness as defined above would mean diameter. The glassfilaments are generally circular in cross section.

The length of the glass filaments is in principle not limited as it issubstantially equal to the length of the sheathed continuousmultifilament strand. For practical reasons of being able to handle thetape however, it may be necessary to cut the sheathed continuousmultifilament strand into a shorter strand. For example the length ofthe sheathed continuous multifilament strand is at least 1 m, forexample at least 10 m, for example at least 50 m, for example at least100 m, for example at least 250 m, for example at least 500 m and/or forexample at most 25 km, for example at most 10 km.

Preferably, the continuous glass multifilament strand in the tape of theinvention comprises at most 2 wt %, preferably in the range from 0.10 to1 wt % of a sizing based on the continuous glass multifilament strand.The amount of sizing can be determined using ISO 1887:2014.

A sizing composition is typically applied to the glass filaments beforethe glass filaments are bundled into a continuous glass multifilamentstrand.

Suitable examples of sizing compositions include solvent-basedcompositions, such as an organic material dissolved in aqueous solutionsor dispersed in water and melt- or radiation cure-based compositions.Preferably, the sizing composition is an aqueous sizing composition.

As described in the art, e.g. in documents EP1460166A1, EP0206189A1 orU.S. Pat. No. 4,338,233, the aqueous sizing composition may include filmformers, coupling agents and other additional components.

The film formers are generally present in effective amount to protectfibres from interfilament abrasion and to provide integrity andprocessability for fibre strands after they are dried. Suitable filmformers are miscible with the polymer to be reinforced. For example; forreinforcing polypropylenes, suitable film formers generally comprisepolyolefin waxes.

The coupling agents are generally used to improve the adhesion betweenthe matrix thermoplastic polymer and the fibre reinforcements. Suitableexamples of coupling agents known in the art as being used for the glassfibres include organofunctional silanes. More particularly, the couplingagent which has been added to the sizing composition is an aminosilane,such as aminomethyl-trimethoxysilane,N-(beta-aminoethyl)-gamma-aminopropyl-trimethoxysilane,gamma-aminopropyl-trimethoxysilanegamma-methylaminopropyl-trimethoxysilane,delta-aminobutyl-triethoxysilane, 1,4-aminophenyl-trimethoxysilane.Preferably, in the tape of the invention, the sizing compositioncontains an aminosilane to enable a good adhesion to the thermoplasticmatrix. The sizing composition may further comprise any other additionalcomponents known to the person skilled in the art to be suitable forsizing compositions. Suitable examples include but are not limited tolubricants (used to prevent damage to the strands by abrasion)antistatic agents, crosslinking agents, plasticizers, surfactants,nucleation agents, antioxidants, pigments as well as mixtures thereof.

Typically, after applying the sizing composition to the glass filaments,the filaments are bundled into the continuous glass multifilamentstrands and then wound onto bobbins to form a package.

In the tape of the invention, the impregnated continuous multifilamentstrand is prepared from a continuous glass multifilament strand and animpregnating agent and in particular by applying an impregnating agentto the continuous glass multifilament strand preferably in an amountfrom 0.50 to 18.0 wt %, for example from 0.5 to 10.0 wt % or for examplefrom 10.0 to 18.0 wt % based on the sheathed continuous multifilamentstrands.

The optimal amount of impregnating agent applied to the continuous glassmultifilament strand depends on the polymer sheath, on the size(diameter) of the glass filaments forming the continuous glass strand,and on the type of sizing composition. Typically, the amount ofimpregnating agent applied to the continuous glass multifilament strandis for example at least 0.50 wt %, preferably at least 1.0 wt %,preferably at least 1.5 wt %, preferably at least 2 wt %, preferably atleast 2.5 wt % and/or at most 10.0 wt %, preferably at most 9.0 wt %,more preferably at most 8.0 wt %, even more preferably at most 7.0 wt %,even more preferably at most 6.0 wt %, even more preferably at most 5.5wt %, or for example at least 10.0 wt %, preferably at least 11 wt %,preferably at least 12 wt % and/or at most 18 wt %, preferably at most16 wt %, preferably at most 14% based on the amount of sheathedcontinuous multifilament strands. Preferably, the amount of impregnatingagent is in the range from 1.5 to 8 wt %, even more preferably in therange from 2.5 wt % to 6.0 wt % based on the sheathed continuousmultifilament strand. A higher amount of impregnating agent increasesthe Impact Energy per unit of thickness (J/mm). However, for reasons ofcost-effectiveness and low emissions (volatile organic compounds) andmechanical properties, the amount of impregnating agent should also notbecome too high.

For example, the ratio of impregnating agent to continuous glassmultifilament strand is in the range from 1:4 to 1:30, preferably in therange from 1:5 to 1:20.

Preferably, the viscosity of the impregnating agent is in the range from2.5 to 200 cSt at 160° C., more preferably at least 5.0 cSt, morepreferably at least 7.0 cSt and/or at most 150.0 cSt, preferably at most125.0 cSt, preferably at most 100.0 cSt at 160° C.

An impregnating agent having a viscosity higher than 100 cSt isdifficult to apply to the continuous glass multifilament strand. Lowviscosity is needed to facilitate good wetting performance of thefibres, but an impregnating agent having a viscosity lower than 2.5 cStis difficult to handle, e.g., the amount to be applied is difficult tocontrol; and the impregnating agent could become volatile. For purposeof the invention, unless otherwise stated, the viscosity of theimpregnating agent is measured in accordance with ASTM D 3236-15(standard test method for apparent viscosity of hot melt adhesives andcoating materials, Brookfield viscometer Model RVDV 2, #27 spindle, 5r/min) at 160° C.

Preferably, the melting point of (that is the lowest melting temperaturein a melting temperature range) the impregnating agent is at least 20°C. below the melting point of the thermoplastic polymer composition.More preferably, the impregnating agent has a melting point of at least25 or 30° C. below the melting point of the thermoplastic polymercomposition. For instance, when the thermoplastic polymer compositionhas a melting point of about 160° C., the melting point of theimpregnating agent may be at most about 140° C.

Suitable impregnating agents are compatible with the thermoplasticpolymer to be reinforced, and may even be soluble in said polymer. Theskilled man can select suitable combinations based on general knowledge,and may also find such combinations in the art.

Suitable examples of impregnating agents include low molar masscompounds, for example low molar mass or oligomeric polyurethanes,polyesters such as unsaturated polyesters, polycaprolactones,polyethyleneterephthalate, poly(alpha-olefins), such as highly branchedpolyethylenes and polypropylenes, polyamides, such as nylons, and otherhydrocarbon resins.

For reinforcing polypropylenes, the impregnating agent preferablycomprises highly branched poly(alpha-olefins), such as highly branchedpolyethylenes, modified low molecular weight polypropylenes, mineraloils, such as, paraffin or silicon and any mixtures of these compounds.

The impregnating agent preferably comprises at least 20 wt %, morepreferably at least 30 wt %, more preferably at least 50 wt %, forexample at least 99.5 wt %, for example 100 wt % of a branchedpoly(alpha-olefin), most preferably a branched polyethylene. To allowthe impregnating agent to reach a viscosity of from 2.5 to 200 cSt at160° C., the branched poly(alpha-olefin) may be mixed with an oil,wherein the oil is chosen from the group consisting of mineral oils,such as a paraffin oil or silicon oil; hydrocarbon oils; and anymixtures thereof.

Preferably, the impregnating agent is non-volatile, and/or substantiallysolvent-free. In the context of the present invention, non-volatilemeans that the impregnating agent has a boiling point or range higherthan the temperatures at which the impregnating agent is applied to thecontinuous multifilament glass strand. In the context of presentinvention, “substantially solvent-free” means that impregnating agentcontains less than 10 wt % of solvent, preferably less than 5 wt % ofsolvent based on the impregnating agent. In a preferred embodiment, theimpregnating agent does not contain any organic solvent.

The impregnating agent may further be mixed with other additives knownin the art. Suitable examples include lubricants; antistatic agents; UVstabilizers; plasticizers; surfactants; nucleation agents; antioxidants;pigments; dyes; and adhesion promoters, such as a modified polypropylenehaving maleated reactive groups; and any combinations thereof, providedthe viscosity remains within the desired range. Any method known in theart may be used for applying the liquid impregnating agent to thecontinuous glass multifilament strand. The application of the liquidimpregnating agent may be performed using a die. Other suitable methodsfor applying the impregnating agent to the continuous multifilamentstrands include applicators having belts, rollers, and hot meltapplicators. Such methods are for example described in documentsEP0921919B1, EP0994978B1, EP0397505B1, WO2014/053590A1 and referencescited therein. The method used should enable application of a constantamount of impregnating agent to the continuous multifilament strand.

The polymer sheath consists of a thermoplastic polymer composition.

Preferably, the melt flow rate (MFR) of the thermoplastic polymer is inthe range from 20 to 150 dg/min, preferably in the range from 25 to 120dg/min, for example in the range from 35 to 100 dg/min as measuredaccording to ISO1133 (2.16 kg/230° C.).

The thermoplastic polymer composition preferably comprises athermoplastic polymer. Suitable examples of thermoplastic polymersinclude but are not limited to polyamide, such as polyamide 6,polyamide, 66 or polyamide 46; polyolefins, for example polypropylenesand polyethylenes; polyesters, such as polyethylene terephthalate,polybutylene terephthalate; polycarbonates; polyphenylene sulphide;polyurethanes and mixtures thereof.

The thermoplastic polymer is preferably a polyolefin, more preferably apolyolefin chosen from the group of polypropylenes or elastomers ofethylene and α-olefin comonomer having 4 to 8 carbon atoms, and anymixtures thereof.

In one embodiment, preferably the thermoplastic polymer compositioncomprises at least 80 wt % of a thermoplastic polymer, for example atleast 90 wt % polyolefin, at least 93 wt %, for example at least 95 wt%, for example at least 97 wt % of thermoplastic polymer, for example atleast 98 wt % or for example at least 99 wt % of a thermoplastic polymerbased on the thermoplastic polymer composition. In a special embodiment,the thermoplastic polymer composition consists of a thermoplasticpolymer.

In another embodiment, the thermoplastic polymer composition comprisesat least 60 wt %, for example at least 70 wt %, for example at least 75wt % and/or at most 99 wt %, for example at most 95 wt %, for example atmost 90 wt % thermoplastic polymer.

The polypropylene may for example be a propylene homopolymer or a randompropylene-α-olefin copolymer or a heterophasic propylene copolymer.

A propylene homopolymer can be obtained by polymerizing propylene undersuitable polymerization conditions. A propylene copolymer can beobtained by copolymerizing propylene and one or more other α-olefins,preferably ethylene, under suitable polymerization conditions. Thepreparation of propylene homopolymers and copolymers is, for example,described in Moore, E. P. (1996) Polypropylene Handbook.

Polymerization, Characterization, Properties, Processing, Applications,Hanser Publishers: New York.

The α-olefin in the random propylene α-olefin copolymer is for examplean α-olefin chosen from the group of α-olefin having 2 or 4 to 10C-atoms, preferably ethylene, 1-butene, 1-hexene or any mixturesthereof. The amount of α-olefin is preferably at most 10 wt % based onthe propylene α-olefin copolymer, for example in the range from 2-7 wt %based on the propylene α-olefin copolymer.

Polypropylenes can be made by any known polymerization technique as wellas with any known polymerization catalyst system. Regarding thetechniques, reference can be given to slurry, solution or gas phasepolymerizations; regarding the catalyst system reference can be given toZiegler-Natta, metallocene or single-site catalyst systems. All are, inthemselves, known in the art.

Heterophasic propylene copolymers are generally prepared in one or morereactors, by polymerization of propylene in the presence of a catalystand subsequent polymerization of a propylene-α-olefin mixture. Theresulting polymeric materials are heterophasic, but the specificmorphology usually depends on the preparation method and monomer ratio.

The heterophasic propylene copolymer as defined herein consists of apropylene-based matrix and a dispersed ethylene-α-olefin copolymer.

The propylene-based matrix typically forms the continuous phase in theheterophasic propylene copolymer.

The propylene-based matrix consists of a propylene homopolymer and/or apropylene-α-olefin copolymer consisting of at least 70% by mass ofpropylene and up to 30% by mass of α-olefin, for example ethylene, forexample consisting of at least 80% by mass of propylene and up to 20% bymass of α-olefin, for example consisting of at least 90% by mass ofpropylene and up to 10% by mass of α-olefin, based on the total mass ofthe propylene-based matrix.

Preferably, the α-olefin in the propylene-α-olefin copolymer is selectedfrom the group of α-olefins having 2 or 4-10 carbon atoms and ispreferably ethylene.

Preferably, the propylene-based matrix consists of a propylenehomopolymer.

The melt flow index (MFI) of the propylene-based matrix (before it ismixed into the composition of the invention) may be in the range of forexample 0.3 to 200 dg/min as measured according to ISO1133 (2.16 kg/230°C.).

The propylene-based matrix is for example present in an amount of 50 to85 wt % based on the total heterophasic propylene copolymer.

Besides the propylene-based matrix, the heterophasic propylene copolymeralso consists of a dispersed ethylene-α-olefin copolymer. The dispersedethylene-α-olefin copolymer is also referred to herein as the ‘dispersedphase’. The dispersed phase is embedded in the heterophasic propylenecopolymer in a discontinuous form.

The MFI of the dispersed ethylene α-olefin copolymer may vary betweenwide range and may for example be in the range from for example be inthe range from 0.001 to 10 dg/min (measured according to ISO1133 (2.16kg/230° C. as calculated using the following formula:

${{MFR}\mspace{14mu}{EPR}} = {10^{\hat{}}\left( \frac{{{Log}\mspace{20mu}{MFR}\mspace{14mu}{heterophasic}} - {{matrix}\mspace{14mu}{content}*{Log}\mspace{14mu}{MFR}\mspace{14mu}{PP}}}{{rubber}\mspace{14mu}{content}} \right)}$

wherein MFR heterophasic is the melt flow rate of the heterophasicpropylene copolymer measured according to ISO1133 (2.16 kg/230° C.),

MFR PP is the MFR of the propylene-based matrix of the heterophasicpropylene copolymer measured according to ISO1133 (2.16 kg/230° C.)

matrix content is the amount of propylene-based matrix in theheterophasic propylene copolymer in wt % and

rubber content is the amount of ethylene α-olefin copolymer in theheterophasic propylene copolymer in wt %.

The dispersed ethylene-α-olefin copolymer is for example present in anamount of 50 to 15 wt % based on the total heterophasic propylenecopolymer.

For example, the amount of ethylene in the ethylene-α-olefin copolymer(RCC2) is in the range of 20-65 wt % based on the ethylene-α-olefincopolymer.

The amounts of the propylene-based matrix and the dispersedethylene-α-olefin copolymer, as well as the amount of ethylene in theethylene α-olefin copolymer may be determined by ¹³C-NMR, as is wellknown in the art.

In the heterophasic polypropylene, the sum of the total weight of thepropylene-based matrix and the total weight of the dispersedethylene-α-olefin copolymer is 100 wt %

The α-olefin in the ethylene-α-olefin copolymer is preferably chosenfrom the group of α-olefins having 3 to 8 carbon atoms and any mixturesthereof, preferably the α-olefin in the ethylene-α-olefin copolymer ischosen from the group of α-olefins having 3 to 4 carbon atoms and anymixture thereof, more preferably the α-olefin is propylene, in whichcase the ethylene-α-olefin copolymer is ethylene-propylene copolymer.Examples of suitable α-olefins having 3 to 8 carbon atoms, which may beemployed as ethylene comonomers to form the ethylene α-olefin copolymerinclude but are not limited to propylene, 1-butene, 1-pentene,4-methyl-1-pentene, 1-hexen, 1-heptene and 1-octene.

The elastomer of ethylene and α-olefin comonomer having 4 to 8 carbonatoms may for example have a density in the range from 0.850 to 0.915g/cm³. Such elastomers are sometimes also referred to as plastomers.

The α-olefin comonomer in the elastomer is preferably an acyclicmonoolefin such as 1-butene, 1-pentene, 1-hexene, 1-octene, or4-methylpentene.

Accordingly, the elastomer is preferably selected from the groupconsisting of ethylene-1-butene copolymer, ethylene-1-hexene copolymer,ethylene-1-octene copolymer and mixtures thereof, more preferablywherein the elastomer is selected from ethylene-1-octene copolymer. Mostpreferably, the elastomer is an ethylene-1-octene copolymer.

Preferably, the density of the elastomer is at least 0.865 g/cm³ and/orat most 0.910 g/cm³. For example, the density of the elastomer is atleast 0.850, for example at least 0.865, for example at least 0.88, forexample at least 0.90 and/or for example at most 0.915, for example atmost 0.910, for example at most 0.907, for example at most 0.906 g/cm³.More preferable the density of the elastomer is in the range from 0.88up to an including 0.907 g/cm³, most preferably, the density of theelastomer is in the range from 0.90 up to and including 0.906 g/cm³.

Elastomers which are suitable for use in the current invention arecommercially available for example under the trademark EXACT™ availablefrom Exxon Chemical Company of Houston, Tex. or under the trademarkENGAGE™ polymers, a line of metallocene catalyzed plastomers availablefrom Dow Chemical Company of Midland, Mich. or under the trademarkTAFMER™ available from MITSUI Chemicals Group of Minato Tokyo or underthe trademark Nexlene™ from SK Chemicals.

The elastomers may be prepared using methods known in the art, forexample by using a single site catalyst, i.e., a catalyst the transitionmetal components of which is an organometallic compound and at least oneligand of which has a cyclopentadienyl anion structure through whichsuch ligand bondingly coordinates to the transition metal cation. Thistype of catalyst is also known as “metallocene” catalyst. Metallocenecatalysts are for example described in U.S. Pat. Nos. 5,017,714 and5,324,820. The elastomer s may also be prepared using traditional typesof heterogeneous multi-sited Ziegler-Natta catalysts.

Preferably, the elastomer has a melt flow index of 0.1 to 40 dg/min(ISO1133, 2.16 kg, 190° C.), for example at least 1 dg/min and/or atmost 35 dg/min. More preferably, the elastomer has a melt flow index ofat least 1.5 dg/min, for example of at least 2 dg/min, for example of atleast 2.5 dg/min, for example of at least 3 dg/min, more preferably atleast 5 dg/min and/or preferably at most 30 dg/min, more preferably atmost 20 dg/min, more preferably at most 10 dg/min measured in accordancewith ISO 1133 using a 2.16 kg weight and at a temperature of 190° C.

Preferably, the amount of ethylene incorporated into the elastomer is atleast 50 mol %. More preferably, the amount of ethylene incorporatedinto the elastomer is at least 57 mol %, for example at least 60 mol %,at least 65 mol % or at least 70 mol %. Even more preferably, the amountof ethylene incorporated into the elastomer is at least 75 mol %. Theamount of ethylene incorporated into the elastomer may typically be atmost 97.5 mol %, for example at most 95 mol % or at most 90 mol %.

The thermoplastic polymer composition may contain the usual additives,for instance nucleating agents and clarifiers, stabilizers, releaseagents, fillers, peroxides, plasticizers, anti-oxidants, lubricants,antistatics, cross linking agents, scratch resistance agents, highperformance fillers, pigments and/or colorants, impact modifiers, flameretardants, blowing agents, acid scavengers, recycling additives,coupling agents, anti-microbials, anti-fogging additives, slipadditives, anti-blocking additives, polymer processing aids and thelike. Such additives are well known in the art. The skilled person willknow how to choose the type and amount of additives such that they donot detrimentally influence the aimed properties. In a specialembodiment, the thermoplastic polymer composition consists of thethermoplastic polymer and additives.

Preferably, the amount of impregnated continuous multifilament strand isin the range of 10 to 70 wt %, for example in the range from 15 to 70 wt%, for example in the range from 20 to 70 wt % or for example in therange from 25 to 70 wt % based on the sheathed continuous multifilamentstrands. Preferably, the sum of the amount of impregnated continuousmultifilament strand and the polymer sheath is 100 wt %.

Although the invention has been described in detail for purposes ofillustration, it is understood that such detail is solely for thatpurpose and variations can be made therein by those skilled in the artwithout departing from the spirit and scope of the invention as definedin the claims.

It is further noted that the invention relates to all possiblecombinations of features described herein, preferred in particular arethose combinations of features that are present in the claims. It willtherefore be appreciated that all combinations of features relating tothe composition according to the invention; all combinations of featuresrelating to the process according to the invention and all combinationsof features relating to the composition according to the invention andfeatures relating to the process according to the invention aredescribed herein.

It is further noted that the term ‘comprising’ does not exclude thepresence of other elements. However, it is also to be understood that adescription on a product/composition comprising certain components alsodiscloses a product/composition consisting of these components. Theproduct/composition consisting of these components may be advantageousin that it offers a simpler, more economical process for the preparationof the product/composition. Similarly, it is also to be understood thata description on a process comprising certain steps also discloses aprocess consisting of these steps. The process consisting of these stepsmay be advantageous in that it offers a simpler, more economicalprocess.

1. A process for the production of a tape comprising a plurality ofsheathed continuous multifilament strands, wherein each of the sheathedcontinuous multifilament strands comprises a core that extends in thelongitudinal direction and a polymer sheath which intimately surroundssaid core, wherein each of the cores comprises an impregnated continuousmultifilament strand comprising at least one continuous glassmultifilament strand, wherein the at least one continuous glassmultifilament strand is impregnated with an impregnating agent, whereinthe process comprises the steps of: d) providing the plurality ofsheathed continuous multifilament strands, e) placing the plurality ofsheathed continuous multifilament strands in parallel alignment in thelongitudinal direction, f) grouping the plurality of sheathed continuousmultifilament strands, wherein steps e) and f) are performed such thatthe sheathed continuous multifilament strand can be consolidated and g)subsequently consolidating the plurality of sheathed continuousmultifilament strands to form the tape, wherein the sheathed continuousmultifilament strands are prepared by the sequential steps of a)unwinding from a package the continuous glass multifilament strands, b)applying the impregnating agent to the continuous glass multifilamentstrands to form the impregnated continuous multifilament strands and c)applying the sheath of the thermoplastic polymer composition around theimpregnated continuous multifilament strands to form the sheathedcontinuous multifilament strands, wherein the sheathed continuousmultifilament strands of step d) are the sheathed continuousmultifilament strands obtained by step c) and wherein the sheathedcontinuous multifilament strands of step d) are subjected to step e)without cutting.
 2. The process according to claim 1, wherein thecontinuous glass multifilament strands unwound in step a), theimpregnated continuous multifilament strands formed in step b), thesheathed continuous multifilament strands formed in step c) are not cutduring steps a)-g).
 3. The process according to claim 1, wherein theprocess further comprises step h) of cutting the tape obtained by stepg) into desired length.
 4. The process according to claim 1, whereinsteps e) and f) are performed by pulling the plurality of sheathedcontinuous multifilament strands through a slit die.
 5. The processaccording to claim 1, wherein the consolidation of the plurality ofsheathed continuous multifilament strands is performed in aconsolidation unit, for example using a belt press.
 6. The processaccording to claim 1, wherein step g) is performed by sequential stepsof g1) heating and applying pressure on the plurality of sheathedcontinuous multifilament strand to obtain a product made of consolidatedstrands and g2) cooling and solidifying the product obtained by stepg1), e.g. by chill rolls, a water bath, a blower a fan or a high speedair knife.
 7. The process according to claim 6, wherein step g1) isperformed by sequential steps of g1a) melting the plurality of sheathedcontinuous multifilament strand to merge the strands, e.g. by hot rolls,flat belts, an oven or a belt press and g1b) applying pressure on theproduct obtained by step g1a) to adjust its thickness, e.g. bycalendaring rolls.
 8. The process according to claim 1, wherein theamount of impregnating agent is 0.50 to 18 wt %, for example from 0.5 to10.0 wt % or for example from 10.0 to 18.0 wt %, more preferably 1.5 to8 wt %, even more preferably in the range from 2.5 wt % to 6.0 wt %based on the sheathed continuous multifilament strand, and/or whereinthe impregnating agent has a melting point of at least 20° C. below themelting point of the thermoplastic polymer composition and has aviscosity of from 2.5 to 200 cSt at 160° C., and/or wherein thecontinuous glass multifilament strand comprises at most 2 wt % of asizing composition based on the continuous glass multifilament strand,and/or wherein the sheath consists of a thermoplastic polymercomposition, wherein the thermoplastic polymer composition comprises atleast 60 wt %, for example at least 80 wt % of a thermoplastic polymer,and/or wherein the amount of the impregnated continuous multifilamentstrand is in the range of 10 to 70 wt %, for example 25 to 70 wt %,based on the sheathed continuous multifilament strand and wherein theamount of the sheath is in the range of 30 to 90 wt %, for example 30 to75 wt %, based on the sheathed continuous multifilament strand andwherein the sum of the amount of impregnated continuous multifilamentstrand and the sheath is 100 wt %.
 9. The process according to claim 1,wherein the thermoplastic polymer is a polyolefin, preferably whereinthe polyolefin is chosen from the group of polypropylenes or elastomersof ethylene and α-olefin comonomer having 4 to 8 carbon atoms, and anymixtures thereof.
 10. The process according to claim 1, wherein the meltflow rate of the thermoplastic polymer composition is in the range from20 to 150 dg/min, preferably in the range from 25 to 120 dg/min, forexample in the range from 35 to 100 dg/min as measured according toISO1133 (2.16 kg/230° C.).
 11. The process according to claim 1, whereinthe thermoplastic polymer composition comprises at least 80 wt % of thethermoplastic polymer, for example at least 90 wt % polyolefin, at least93 wt %, for example at least 95 wt %, for example at least 97 wt % ofthermoplastic polymer, for example at least 98 wt % or for example atleast 99 wt % of a thermoplastic polymer based on the thermoplasticpolymer composition.
 12. A tape obtained by or obtainable by the processaccording to claim
 1. 13. (canceled)
 14. An article comprising the tapeof claim
 12. 15. (canceled)
 16. The article of claim 14 comprising aplurality of the tapes in the form of a laminate, a woven fabric, orboth.
 17. The article of claim 14 which is a component in an automotiveapplication.